Chair control pressure plate having replaceable thrust bearings



Ud. 11, 1966 F. DOERNER CHAIR CONTROL PRESSURE PLATE HAVING REPLACEABLETHRUST BEARINGS 2 Sheets-Sheet 1 ATTOR EY Filed Jan. 3, 196 6 @ct, H,1966 F. DOERNER 3,278,228

CHAIR CONTROL PRESSURE PLATE HAVING REPLACEABLE THRUST BEARINGS FiledJan. 5, 1966 2 Sheets-Sheet z INVENTOK FRANK DOERNEK ATTORNEY UnitedStates Patent 3,278,228 CHAIR CONTROL PRESSURE PLATE HAVING REPLACEABLETHRUST BEARINGS Frank Doerner, Waterloo, Ontario, Canada, assignor toDoerner Products (30., Limited, Waterloo, Ontario,

Canada, a corporation of Untario, Canada Filed Jan. 3, 1966, Ser. No.518,226 7 Claims. (Cl. 297-303) This invention relates to a chaircontrol for tilter chairs and in particular to a removable pressureplate for the tension spring, said pressure plate having replaceablethrust bearings.

Chair controls for tilting chairs presently in use comprise a base, achair support post which is screw threaded so as to provide for avertical adjustment of the height of the chair seat, a fixed framecarried by the post, a second frame pivotally mounted on the fixed framefor limited pivotal movement about a horizontal axis relative to thefixed frame, said second frame having means for attaching it to a chairseat and biasing means yieldably interconnecting said frames and urgingsaid second frame to a stop position relative to the fixed frame andyieldably resisting pivotal movement of the second frame away from saidstop position under a force applied by an occupant of the chair, saidbiasing means comprising a substantially rigid tie-rod having one endfastened to the second frame and the opposite end extending beyond thefixed frame, a pressure plate permanently mounted on the fixed frame andhaving rotative movement about an axis parallel to the horizontal axisand a spring mounted on the connecting member and having one end seatedon said pressure plate and the other end engaged by an adjusting handlewhich is threaded on to the free end of the tie-rod. A disadvantage ofthe foregoing construction was that the bearings for the pressure platecould not be replaced when they became worn and consequently thecomplete chair control because of its construction had to be discardedand replaced by a new chair control.

It is therefore an object of the present invention to provide a chaircontrol for a tilting chair having an easily removable pressure plate sothat when the bearings become Worn the plate can be removed and thebearings replaced. Other and further advantages of the present inventionwill be apparent from the following description which is illustrated bythe accompanying drawings in which:

FIGURE 1 is a perspective side elevation of a tilter chair embodying theinvention which is the subject of the present application.

FIGURE 2 is a cross-section on the line 22 of FIGURE 1.

FIGURE 3 is a fragmentary view of the pivotal connection between thepressure plate and the pivotally mounted frame.

FIGURE 4 is an exploded view of the chair control illustrated in FIGURE1.

FIGURE 5 is an exploded view of an alternative construction of thepressure plate shown in FIGURES l to 5.

FIGURE 6 is a fragmentary view, on an enlarged scale, to show thepivotal mounting for the pressure plate according to this alternativeconstruction.

FIGURE 7 is a plan view, partly in cross-section of the chair controlshown in FIGURE 5.

FIGURE 8 is a cross-section on the line 8--8 of FIG- URE 7.

The invention will first be described with reference to the embodimentdisclosed in FIGURES l to 4. The chair per se comprises a mobile base 10which is provided with a conventional support post 11, the chair controldevice which is generally indicated by the letter A and having a "icefixed frame mounted on the top end of the post 11 and a pivotallymounted frame pivotally connected to the fixed frame which fixed frameis rigidly connected to the underside of the chair seat indicated by thenumeral 12. The pivotally mounted frame is yieldably connected to thefixed frame by the components which will hereafter be described inrelation to the invention of the present application.

The fixed frame comprises a base plate 13 having a pair of spaced apartupright arms 14, 15 formed integrally therewith to thereby form asubstantially U-shaped frame. The base plate carries a second plate 16in spatial relationship, the plate 16 being formed with a centralopening 17 which registers with a corresponding opening (not shown) inthe base plate 13. The upper end of the post 11 is fitted into theopenings referred to with a press fit so that the fixed frame is rigidlyand firmly supported on the top end of the post. The complete chairassembly can revolve about the vertical axis of the post 11 The secondframe member comprises a substantially U-shaped strap having a baseplate 18 and outwardly extending arms 19 and 20, the second frame beingso dimensioned that the arms 14, 15 of the fixed frame fit nicelytherebetween with the base plate 18 perpendicular to the base plate 13.The two frames are pivotally connected by means of the pivot rod 21 withthe edge of the arms 14, 15 resting against the base plate 18 to providea stop position for the second frame as hereinafter described wherebythe chair is retained in position. The pivot 21 is located to permitdownward movement of the second frame away from the stop position. Thesecond frame which comprises the base plate 18 and the arms 19 and 20 isconnected to the chair seat 12 through the medium of the attachingbrackets 22 and 23 which are attached to the arms 19 and 20respectively.

The biasing means for yieldably interconnecting the fixed frame and thesecond frame, comprises the following components namely a tie-rod 24which is entered through a hole formed in the base 18 with its enlargedhead 25 engaged against the outside surface of the base plate; a springassembly mounted on the opposite or free end of the tie-rod, saidassembly comprising a compression spring 26, a pressure plate 27, acollar 28 and an adjusting handle 29, the spring being captured betweenthe pressure plate 27 and the collar 28. The pressure plate is providedwith a pair of mounting arms 30 and 31, one at each end, each arm havingan outwardly extending pivot pin 32, each pin carrying a replaceablenylon bearing 33. The contiguous edges of the arms 14 and 15 are formedwith recesses or slots 35 and 36 respectively which are positioned anddimensioned to receive the nylon bearings 33.

The assembly and dismantling of the biasing means is quite simple andsubstantially self-explanatory from the drawings. FIGURE 1 illustratesthe chair control completely assembled. The pressure plate of thepresent invention greatly simplifies the manufacturing procedures forthe chair control and the assembly of the components into the completeunit. To replace the bearings 33 as and when they become Worn, the firststep is of course, to re move the adjusting handle 29 which permits thecollar 28, the compression spring 26 and the pressure plate 27 to beremoved. It is then possible to remove the nylon bearings that have beenworn and replace them and then reassemble the biasing means asillustrated.

The alternative structure shown in FIGURES 5, 6, 7 and 8 is essentiallythe same structure as shown in the preceding views and consequently thesame reference numerals will be used in connection with the commoncomponents and parts. The only difference between the constructionsresides in the mounting of the pressure plate 27 but the mounting isequivalent to the mounting of the pressure plate shown and describedwith relation to FIG- URES 1 to 4 inclusive. Referring now specificallyto the pressure plate 27a shown in FIGURES 5 to 8 inclusive, it will beseen that the mounting arms 30a, 31a are provided with open end slots37, 38 having the open ends facing the fixed frame previously describedwith the upright arms 14, 15 thereof being provided with pivots 32a onwhich 'are mounted nylon bearings 33a. The pivots 32a with the nylonbearings 33a mounted therein are received in the slots 37, 38 wherebythe pressure plate 27a is pivotally mounted to the arms 14, 15 in such amanner as to be easily disconnected therefrom.

This structure which has been described with reference to FIGURES 5 to 8is used in exactly the same manner as that previously described withreference to FIGURES 1 to 4.

What I claim is:

1. In a chair control for a tilting chair having a base, a chair supportmember, a fixed frame carried by the member, a second frame pivotallymounted on the fixed frame for limited pivotal movement about ahorizontal axis relative to the fixed frame, said second frame havingmeans for attaching it to a chair seat, and biasing means yieldablyconnecting the fixed frame and the second frame and urging said secondframe to a stop position relative to the fixed frame and yieldablyresisting pivotal movement of the second frame away from said stopposition under a force applied by an occupant of the chair, said biasingmeans comprising a substantially rigid connecting member disposed in ahorizontal plane transverse to the horizontal axis and having one endfastened to one of said frame members and the opposite end extendingbeyond the other frame member, a pressure plate removably carried bysaid other frame and having rotative movement about an axis parallel tothe horizontal axis and a spring mounted on the connecting member andhaving one end seated on said pressure plate and the other end connectedto the said opposite end of the connecting member.

2. A chair control for a tilting chair according to claim 1 in which thechair support is a post; the fixed frame is a U-shaped upright memberhaving upwardly extending arms and an apertured base for receiving saidpost and the second frame consists of a U-shaped strap with its baseperpendicular to the apertured base and its arms overlapping the arms ofthe U-shaped upright member, and the pivotal mounting comprises a pivotpin connecting the arms for said pivotal movement.

3. A chair control for a tilting chair accord-ing to claim 1 in whichthe frames comprise a pair of U-shaped straps pivotally connectedtogether for limited movement of the second U-shaped strap away from thestop position, the fixed U-shaped strap being located within the secondstrap and the pivotal connection comprises a pivot pin connecting thearms of the U-shaped straps.

4. A chair control for a tilting chair according to claim 2 in which therigid connecting member is removably connected to the base of theU-shaped strap and the pressure plate engages against the upwardlyextending arms.

5. A chair control for a tilting chair according to claim 2 in which therigid connecting member is removably connected to the base of the secondframe and the pressure plate is provided with outwardly projecting pivotpins and the upwardly extending arms are formed with outwardly openingpin receiving slots.

6. A chair control for a tilting chair according to claim 2 in which therigid connecting member is removably connected to the base of theU-shaped strap and the upwardly extending arms are each provided with apivot pin receivable in pin receiving slots formed in the pressureplate.

7. A chair control for a tilting chair according to claim 1 in which thepressure plate is removably carried by the second frame by pin and slotmeans.

References Cited by the Examiner UNITED STATES PATENTS 2,093,319 9/1937Herold 297-301 X 2,228,719 1/1941 Bolens 297303 X 2,283,062 5/1942Herold 297-303 X 2,545,950 3/1951 Fox 297303 X 2,650,646 9/1953 Heroldet al 29730l 2,818,911 1/1958 Syak 297303 X 2,845,922 8/1958 Cramer297303 FRANK B. SHERRY, Primary Examiner.

G. O. FINCH, Assistant Examiner.

1. IN A CHAIR CONTROL FOR A TILTING CHAIR HAVING A BASE, A CHAIR SUPPORTMEMBER, A FIXED FRAME CARRIED BY THE MEMBER, A SECOND FRAME PIVOTALLYMOUNTED ON THE FIXED FRAME FOR LIMITED PIVOTAL MOVEMENT ABOUT AHORIZONTAL AXIS RELATIVE TO THE FIXED FRAME, SAID SECOND FRAME HAVINGMEANS FOR ATTACHING IT TO A CHAIR SEAT, AND BIASING MEANS YIELDABLYCONNECTING THE FIXED FRAME AND THE SECOND FRAME AND URGING SAID SECONDFRAME TO A STOP POSITION RELATIVE TO THE FIXED FRAME AND YIELDABLYRESISTING PIVOTAL MOVEMENT OF THE SECOND FRAME AWAY FROM SAID STOPPOSITION UNDER A FORCE APPLIED BY AN OCCUPANT OF THE CHAIR, SAID BIASINGMEANS COMPRISING A SUBSTANTIALLY RIGID CONNECTING MEMBER DISPOSED IN AHORIZONTAL PLANE TRANSVERSE TO THE HORIZONTAL AXIS AND HAVING ONE ENDFASTENED TO ONE OF SAID FRAME MEMBERS AND THE OPPOSITE END EXTENDINGBEYOND THE OTHER FRAME MEMBER, A PRESSURE PLATE REMOVABLY CARRIED BYSAID OTHER FRAME AND HAVING ROTATIVE MOVEMENT ABOUT AN AXIS PARALLEL TOTHE HORIZONTAL AXIS AND A SPRING MOUNTED ON THE CONNECTING MEMBER ANDHAVING ONE END SEATED ON SAID PRESSURE PLATE AND THE OTHER END CONNECTEDTO THE SAID OPPOSITE END OF THE CONNECTING MEMBER.